Ala u din Masud (1242-1246) was a Muslim Turkic ruler and the seventh Sultan of Delhi in medieval India during the Mamluk dynasty (or Slave dynasty). He was the son of Rukn ud din Firuz (1236) and the nephew of Razia Sultan (1236-1240). After his predecessor, Muiz ud din Bahram, was murdered by the army in 1242 after years of disorder, the chiefs chose for him to become the next ruler. However, he was more of a puppet for the chiefs and did not actually have much power or influence in the government. Instead, he became infamous for his fondness of entertainment and wine. By 1246, the chiefs became upset with Ala ud din Masud's increasing hunger for more power in the government, and replaced him with Nasir ud din Mahmud (1246-1266), another son of Iltutmish.